Method of isolating and refining tocopherol homologues



United States Patent 3,402,182 METHOD OF ISOLATING AND REFINING TOCOPHEROL HOMOLOGUES Shizumasa Kijima, Toyota, Hino-shi, Tokyo, and Tetsuya Nakamura, Kamikizaki, Urawa-shi, Saitama, Japan, as-

signors to Eisai Co., Ltd., Tokyo, Japan, a corporation of Japan No Drawing. Filed Apr. 28, 1966, Ser. No. 545,830

7 Claims. (Cl. 260-3456) ABSTRACT OF THE DISCLOSURE A process for separating from one another the indithereby eluting first a-tocopherol the weakest in acidity from the resin and then j3-t0coph6r0l and v-tocopherol. o-Tocopherol, the strongest in acidity, will not be eluted from the resin by simply passing the self-dissociating solvent. The method of the present invention further comprises passing a solution of such acid as acetic acid in the self-dissociating solvent, through the column thus eluting o-tocopherol from the resin. By removing the solvent from the respective fractions, tocopherol homologues having high purity can be isolated respectively. B-Tocopherol and -tocopherol will be obtained respectively in fractions which are close to each other. However, this fact is no obstacle to the working of the present invention at all, because there has been discovered no natural oil containvidual members of a tocopherol homologue mixture inmg both P P W and 'YtOCOPhemI simultaneouslyincluding Ot-tOCOPhfilOl, ,B-tocopherol, 'y-tocopherol and 5 The self-dissociating solvents to be used in the present tocopherol in which the tocopherol homologue mixture invention are methanol, allyl alcohol and their mlxture. is adsorbed on an OH-type basic anion exchange resin. A Methianol most F P The exchange to self-dissociating solvent is then passed through the resin used In the Present mventlon must be P Y baslc and 15 thereby eluting, first, the u-tocopherol and the fi-tocopherol prefierablyporous Among i commercial Ion exchange or -tocopherol. Afterwards, a solution of the self-disresms havmg these Propertles are Dowex Dowex sociating solvent and an acid is passed through the resin, 1TX2 Dowex Dowex T (Dow Chflmcal therebydutingthe5 t0cophem1 Amberlite IRA40l, Amberllte IRA-4ll (Rhom and Haas), Diaion SA-lOl, D1a1on SA-20l (Mitsubishi Chemical Ind. Ltd.), Duolite A-40LC and Duolite A-42LC (Chemical Process 00.), etc. These commercial ion This invention relates to a method f Separating a exchange resins are sold usually as a chlorine type. Therecopherol homologue mixture into respective single comfore to the operatlQn Separatmg tocopherol Ponents by using a basic anion exchange resin. homologues, such commerc1al resins must be treated wlth Seven kinds of tocopherol homologues have been dis an aqueous 5011mm. of 5 to 10% alkah hydroxlde 1n covered in natural oils. They exist usually as a mixture f Y the 1011 type to an OH type and then i f two or more kinds For example, wtocopherol, self-dissociating solvent must be passed through the resm copherol and B-tocopherol are contained in soybean oil so as to Keplace the Waterand poppy seed Oil, wtocopherol and 1, t0copher01 are The acid to be used to elute a-tocopherol may beeither contained in cottonseed oil, rapeseed oil and corn oil and {morganlc acld ,Orgamc -fl y q an Orgamc acld wtocopherol and fi tocopherol have been discovered in 1s preferable. Particularly, acetlc ac d glves good results. Wheat germ Oil. Examples of the present lnventlon are given 1n the As methods of separating such tocopherol homologues, followlng there have been discovered such efiective methods as re- 40 E l 1 versed phase paper chromatography, thin layer chromatography and gas chromatography. However, though A glass column (3 cm. x 90 cm.) was charged with each of such separating methods is suited for analytical or 5500 ml. of Dowex l-X2 (50 to 100 meshes). Five liters experimental purposes, only a very small amount of a of an aqueous solution of 4% sodium hydroxide were sample can be treated thereby. There has not yet been passed through the resin, converting the ion type of the known any method of isolating such homologues cheaply resin to OH type. The resin was then washed with distilled on an industrial scale. water until the washing solution became neutral. Then one We have found that these tocopherol homologues show liter of methanol was passed concurrently through the respective dilferent acidities though very slight in a weakly column in order to replace the water with the solvent. self-dissociating solvent (solvents which have a tendency Sixty-two grams of concentrated soybean oil (total tocophto release protons in a slight degree), such as methanol erol concentration was 96.8%; as a result of quantitative and allyl alcohol, and have succeeded in isolating respecdetermination by using a thin layer chromatography, the tive tocopherols from a tocopherol homologue mixture by tocopherol homologue composition was found to consist combining the use of a self-dissociating solvent with the of 9% of (at-tocopherol, 58% 'y-tocopherol and 33% fi-touse of abasic anion exchange resin. copherol) dissolved in 50 ml. of methanol were passed The method of the present invention comprises passing through the column, 10.5 liters of methanol were then a solution of a tocopherol homologue mixture in a selfpassed through so that a-tocopherol and 'y-tocopherol are dissociating solvent such as methanol and allyl alcohol eluted respectively and isolated and then one liter of through an OH-type basic anion exchange resin column acidic methanol contining 5% acetic acid was passed immersed in said self-dissociating solvent and further through in order to elute o-tocopherol. passing said self-dissociating solvent through said resin, 60 The results are shown in the following table:

Amount Weight Purity Eluted Effluent of the of the of the Thin layer Fraction Eifluent Oil (g.) 'Iocopherol Chromatography (1.) in percent Raw material 62. 0 96. 8 a, 'y and fi-Tocopherols. Fraction 1. Methanol. 0.3 2. 7 37. 6 a-Tocopherol. Fraction 2. 1. 2 4. 3 93. 1 Do. Fraction 3. 1. 5 3.5 99. 4 a and 'y-Tocopherols. Fraction 4 do 4. 5 27. 2 99. 1 'yToeopherol. Fraction5 .do H 3.0 4.5 99.3 Do. Fraction6 5% acetic ac1d-methano1 1.0 20.1 97.5 a-Tocopherol.

3 Example 2 A glass column Was charged with 75 ml. of Dowex 1- X1. Seven hundred fifty ml. of an aqueous solution of 4% sodium hydroxide were passed through the resin so and tat-tocopherol and a-tocopherol were eluted respectively and isolated and then 100 liters of acidic methanol containing 3% acetic acid were passed through and fi-tocopherol was eluted.

that the resin is converted to an OH type. The resin was 5 The results are shown in the following table:

Amount Weight Purity Elutcd Fraction Efliuent of the of the ol the Thin layer Eflluent Oil (kg.) Tocopherol Chromatography (percent) Raw material 5. 3 86. 5 a, 7 and -Tocophcrols. Fraction 1 Methanol... 150 0.811 28.9 a-Tocopherol. Fraction 2 300 0. 601 70. 1 a and 'y-Tocopherols. Fraction 3. 300 0. 810 93. 5 0. Fraction 4 360 1.208 96. 3 'y-Tocophcrol. Fraction 5 360 0. 242 94. 9 0. Fraction 6 100 1. 710 87.8 fi-Tooopherol.

washed with water. Two hundred ml. of allyl alcohol were We claim:

then passed concurrently through the column in order to replace the water with the solvent. Twenty g. of concentrated soybean oil (total tocopherol concentration was 86.5%; as a result of quantitative determination by using a thin layer chromatography, the tocopherol homologue composition was found to consist of 21.2% a-tocopherol, 45.1% y-tocopherol and 33.7% o-tocopherol) dissolved in ml. of allyl alcohol were passed through the column, 1900 ml. of allyl alcohol were then passed through and atocopherol and *y-tOcOphefOl were eluted. Then, 200 ml. of acidic allyl alcohol containing 5% acetic acid were passed through and e-tocopherol was eluted.

The results are shown in the following table:

1. The process for separating a tocopherol homologue mixture into components, which comprises adsorbing a tocopherol homologue mixture dissolved in a self-dissociating solvent on an OH-type basic anion exchange resin immersed in said self-dissociating solvent; then passing a further quantity of said self-dissociating solvent as an eluant through said resin to separate and obtain a-lO- copherol and a member selected from the group consisting of ,B-tocopherol and 'y-tocopherol; then passing a solution of an acid and said self-dissociating solvent through said resin to elute and obtain o-tocopherol; removing the solvent from the respective eluates and recovering the respective tocopherols of high purity.

Amount Weight Purity Eluted Fraction Etlluent of the 01 the of the Thin layer Eflluent Oil in g. Tocopherol Chromatography in ml. in Percent Raw material 20. 0 86. 5 a, 'y and 6-Toeopherols. Fraction 1 Allyl alcohol 750 8. 2 68. 7 a and 'y-Topocopherols.

750 3. 91 97. 2 Do. 400 1. 25 96. 8 Do. 240 6. 59 85. 6 -Tocopherol.

Example 3 A multistep glass column (of three steps) having a diameter of 20 cm. was charged with 30 liters of Dowex 1- X2 to 100 meshes). Three hundred liters of an aqueous solution of 4% sodium hydroxide were passed through the resin in order to convert the ion type of the resin to an OH type. The resin was then washed with distilled water until the washings became neutral. Then liters of methanol were passed concurrently through the column, thus replacing the water with the solvent. Then 5.3 kg. of concentrated soybean oil (total tocopherol concentration was 86.5%; as a result of quantitative determination by using a thin layer chromatography, the tocopherol homologue composition was found to consist of 21.2% OL-tO- copherol, 45.1% -tocopherol and 33.7% 6-tocophero1) dissolved in six liters of methanol were passed through the column, 1470 liters of methanol were then passed through 2. The process of claim 1, wherein the a-tocopherol is collected in the first portions of the self-dissociating solvent which are passed through the resin and wherein the tocopherol homologue selected from the group consisting of ,B-tocopherol and 'y-tocopherol is collected in the subsequent portions of the self-dissociating solvent which are passed through the resin.

3. The process of claim 1, wherein said self-dissociating solvent is methanol.

4. The process of claim 1, wherein said self-dissociating solvent is allyl alcohol.

5. The process of claim 1, wherein said OH-type basic anion exchange resin is strongly basic and porous.

6. The process of claim 1, wherein said acid is acetic acid.

7. The process of claim 1, wherein said tocopherol homologue mixture is a concentrated soybean oil.

References Cited UNITED STATES PATENTS 2/1964 Kijima et al. 260-345.6 10/1964 Brown et al 260- 345.6 

